ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
319 
spore forms are easily stained by fuchsin, methylen-blue, or both, and 
by Gram’s method. Under anaerobic conditions the bacillus is easily 
cultivable, especially on grape-sugar gelatin, with the production of 
much gas, the medium being also rapidly liquefied. Milk is coagulated, 
and from it arises a disagreeable odour, the reaction being amphoteric 
or slightly alkaline. On blood-serum at 37° C., growth is rapid, and the 
formation of spores copious and early. This early production of spores 
in blood-serum is one of the chief features which distinguishes it from 
B. enteritidis sporogenes. 
The author regards B. cadaveris sporogenes as the principal cause of 
the putrefaction of dead bodies. 
Grass bacillus ii.* — Under this name Dr, A. Moeller describes a 
bacillus obtained from vegetable refuse. The author’s communication is 
really a contribution to the pleomorphism of bacteria, and deals with an 
organism belonging to the tubercle bacillus group which is resistant to 
acids and alcohol, and which exhibits true branchings. It is easily 
.cultivable, and grows well on the ordinary media. Like the bacilli of 
dung, of timothy grass, and of tuberculosis, it is quite resistant to the 
action of acids and of alcohol, and especially so if the cultures be young. 
It stains by Gram’s method. The bacteria are motile when young. The 
majority are 1-5 p long and 0 * 2-0 • 4 p broad. They are usually bent, 
sometimes Y-shaped, and on glycerin-agar there are long branched and 
unhranched filaments. 
Pure cultures injected into the peritoneal sac of guinea-pigs cause 
death in 4-6 weeks, with appearances indistinguishable from those of 
tuberculosis. 
The most distinctive characteristics of this Grass bacillus ii. is the 
frequent occurrence of true branchings. Like the other two tuberculoid 
bacilli, it was found on vegetable substrata. 
Contagium vivum fiuidum, the Cause of Spotted Disease of Tobacco 
Leaves.f — Herr M. W. Beijerinck, who has for a long time been investi- 
gating the cause of the spotted or mosaic-disease of tobacco leaves, has 
come to the conclusion that the malady is not due to microbes but to a 
contagium vivum fiuidum. When passed through a porcelain filter, the 
juice of a diseased plant, though devoid of bacteria, anaerobic as well as 
aerobic, is found to retain its infective properties. 
That it is a virus fiuidum as opposed to fixum, i.e. not containing cor- 
puscular or morphotic elements, is shown by its diffusibility through agar 
plates, as well as by the fact that cultivations are always sterile. 
The virus attacks only those tissues and organs which are in an active 
condition of growth and of cell-division. It may gain entrance either 
through the leaves or the roots, and appears to be chiefly conveyed along 
the course of the phloem. The virus may be dried, and may pass the 
winter in the soil, without losing its infective power ; even the alcoholic 
extract, dried at 40°, is virulent. It is quite destroyed by boiling. 
In the milder form of the disease, the virus chiefly attacks the chloro- 
phyll granules, but in severer cases the whole of the protoplasm is 
affected. In the mild cases the leaves seem, in the earlier stage, as if 
* Centralbl. Bakt. u. Par., l te Abt., xxv. (1899) pp. 369-73 (1 pi. and 5 figs.). 
t Verhand. Konink. Akad. Wetensch. Amsterdam (2 de Sectie), Deel vi. No. 5, 
22 pp. (2 pis., coloured). 
